The science of this is potentially interesting. What, then, of Rainsongs and newer carbon-fibre instruments? IMHO the issue is the absence of damping. If adhesives have a greater reluctance (look it up if you don't understand it in context) then both the initial resonance and sustain of a top containing adhesives will be reduced. What you don't want is a high initial amplitude that speedily dies - that way lies the execrable sound of the banjo. So in theory an adhesive that did not store energy might make a complex top no less resonant than a simple timber one. The other issue is the pitch of the resonant frequencies. I once played a guitar the body of which was all- aluminium and the boom and carry and sustain were all good - but it was muddy, without individual string voices, and largely without treble bite. Sweet, but lacking presence. But tap a sheet of ally and a sheet of brass and a sheet of steel side by side and they sound different.